Mechanical forensics and ballistics investigations are undertaken in crime investigations, accident reconstructions or other situations in which one or more weapons have been discharged and it is frequently essential to reliably establish an identification of a firearm that fired a given cartridge.
It is well known that bullets and cartridge cases that have been fired from a firearm will bear markings from contact between the bullets or cartridge cases and the surfaces of the firearm with which the bullets and cartridges come into contact. For example, the rifling of the barrel will emboss rifling and other marks on a bullet, and the firing pin, extractor, interior of the breach and face of the bolt will leave markings on the cartridge case. Certain such markings are general to a given type, manufacturer or model of firearm, and may this aid in identifying a firearm, while others are unique to each firearm and may thereby be used to identify a given firearm.
Firearms experts have frequently been able to compare the markings on cartridge cases and bullets, which are traditionally referred to as “scratches and dings” or “ballistic finger prints”, with comparable markings made by a suspect firearm on a test bullet or cartridge casing, and have frequently been able to determine whether a specific firearm fired a given bullet or cartridge casing. In addition, there exist, for example, databases of “ballistic finger prints” or “scratch and ding” images of bullets and cartridges recovered from crime scenes, which may be subsequently used to match a firearm to a given crime scene by matching samples of fired cartridges and bullets with the archived “ballistic finger prints” or “scratch and ding” images.
Ballistic finger prints and scratch and ding markings, however, while traditionally the most useful and most used for identifying a given, specific firearm, are, however, pseudo-repeatable and largely random and non-specific in nature. That is, a cartridge case may be damaged in any of a number of ways before it is recovered for examination, and a bullet is often severely fragmented or deformed when it strikes an object, thereby obscuring the ballistic finger print or scratch and ding evidence on the bullet or cartridge case. In addition, the identification of a spent cartridge case or filed bullet to a specific firearm requires access to the firearm itself, either for direct examination or to fire test bullets and cartridge cases for comparison with the cartridge cases or bullets held in evidence. The firearm itself is also subject to influences between the time of firing a cartridge and bullet and the comparison of the markings on the cartridge or bullet to later fired test cartridges and bullets that may alter the markings made by it on cartridges and bullets. For example, the surfaces of a firearm that impose markings on a bullet or cartridge are subject to wear, corrosion, abrasion and intentional alterations, such as grinding, etching or filing of surfaces and the replacement of original parts with different parts.
In addition, investigators often have limited evidence to work with in order to determine the facts related to the situation at hand, such as when the suspect firearm is unavailable, missing, unrecoverable, damaged or intentionally altered or in instances in which numerous weapons were discharged. For example, it is very common for the perpetrator of a shooting to take a firearm away with him after committing a crime, and often the only evidence left behind is the discharged bullets themselves, if they can be found and are in adequate condition for examination, and spent cartridge cases, if the cartridge cases are available and in condition for examination. Therefore, while scratches, marks and/or other indicia on a spent bullet or cartridge case can assist an investigator with connecting the spent cartridge or bullet with a given firearm, the identification usually requires possession of the firearm itself, for comparison purposes, is often difficult even when the firearm is available.
Currently, such forensic investigations are expensive and time consuming and require personal training and sophisticated equipment that not every law enforcement department has or can afford.
A concept referred to as “Ballistic Tagging”, however, may be used to mark cartridges or bullets or both with specially encoded geometric shapes, holograms, alphanumeric codes, barcodes and other specific coding techniques which are not random and are which are completely repeatable and which are unique to each firearm. Such methods would be more reliable and less expensive and time consuming than traditional methods, and would not require the costly apparatus, imperfect imaging algorithms, image acquisition technical problems, non-standardized procedures and cross jurisdictional procedures and data bases used to store and share “ballistic finger prints” or “scratch and ding” images.
There are currently available a variety of systems for forming or micro-engraving images, shapes or symbols in or on an surface of a component of a firearm that contacts a bullet or cartridge case in such a manner as to permit the imposition of an identifying indicia on a bullet or cartridge case. Examples include such firearm surfaces as the face of a firing pin, the interior of the chamber or barrel of a firearm, or a surface of an extractor or loading mechanism. Any firearm surface coming into contact with a cartridge case with sufficient force or pressure, for example, can result an image, shape of symbol being embossed or otherwise marked on a surface of the cartridge by the normal operation of the firearm, such as the loading, firing or ejection of the cartridge. Such images, shapes or symbols, hereafter referred to generally as “images” or “indicia”, may take many forms, including abstract symbols or brands, letters or numbers, and so on, and are typically formed of raised or indented areas of a surface, such as holes, vias, blind vias or some other form of surface indentation, raised areas formed by etching or machining away of surrounding surfaces, or any combination thereof.
As a result, fired bullets or cartridge cases or both may be left with markings uniquely identifying the firearm from which they were fired as a result of forced contact between the bullets or cartridge cases and metal parts in the firearm bearing such identifying images. Such parts of a firearm may include, for example, an interior face of the chamber, bolt or barrel or an engraved “marker” embedded in or mounted on such a surface, and may be unique to given firearm by the engraving of an image unique to the firearm during manufacture or as a result of a subsequent refitting or retrofitting.
The advantages of such marking of bullets and cartridges can be realized, however, only if there exist suitable identifying indicia and methods, suitable apparatus for simply, inexpensively and reliably imprinting and reading the markings, and suitable apparatus for correlating the markings on a bullet or cartridge with a given firearm.
It is, therefore, an object of the present invention to simplify and therefore to improve the process of fired cartridge and bullet imaging and analysis, to eliminate the need for complex image algorithms, to reduce the chances of human error, and to eliminate at least some of the need for mapping “scratches and dings” and “ballistic finger prints” of fired cartridges and bullets.